Telephone-exchange system.



J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED a. 23 m2.

:Patented Apr. 27 1915.

9 SHEETS-SHEET l.

J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 23, I912. 1,137,372.

Patented Apr. 27, 1915.

9 SHEETS-SHEET 2.

l. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION mm run. 23. 1912.

1,137,372. Patented Apr. 27, 1915.

9 SHEETS-SHEEP 3.

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

' APPLICATION FILED MAR. 23,19IZ. 1,137,372. Patented Apr. 27, 1915.

9 SHEETSSHEET 4.

Qwuewm J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAR. 23, I9IZ. 1,137,372, Patented Apr. 27, 1915.

9 SHEETS-SHEET 5 J. L. WRIGHT. TELEPHONE sxcmmsc SYSTEM.

APPLICATION FILED MAR. 23. I912- Patent-e'd Apr. 27,

9 SHEETS-SHEET 6.

III

98km Ifir e tm W J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED mm. 23. m2.

9 SHEETSSHEET 7.

J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

I. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FlLED MAR. 23. 1912.

Patented Apr. 27, 1915.

9 SHEETS-SHEET 9.

UNITED STATES PATENT OFFICE.

Jos'EPH n WRIGHT, or WASHINGTON, brs'riuc'r or COLUMBIA, Ass'IGNoR, BY MESNE AssIGNMEN'rs, 'ro FREDERICK c. STEVENS, or ATTICA, NEW YORK.

TELEPHOB E-BXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. 27, 1915.

To all whom it may concern Be it known that I, Josnrn L. VVnIGH'r, a citizen of the United States, and resident of \Vashington, District of Columbia, have mvented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

My invention relates to telephone exchange systems, and especially to that class wherein automatic switching mechanism is employed in establishing connections between subscribers.

The object of my invention is to provide improved means for controlling the automatic switching mechanism.

It is customary in systems wherein switching mechanism is employed, to provide suitable impulse devices for driving or controlling the various automatic switches. For instance, in order to connect a switch with a particular group of trunks or lines impulses are transmitted in a predetermined order, and the switches respond to these impulses and are driven to the proper trunks or lines. In systems operated in this manner, it is necessary to have the sending devices, relays. and magnets adjusted or timed, so that they will cooperate so as to effect proper connections.

The object of my invention is to do away with, or avoid all marginal features or fine adjustments between the relays and magnets of the various switches. Instead of provid ing sending devices for driving the switches to the proper trunks or lines, I simply use a. device for controlling the action of the switches, wherein the necessity for transmitting impulses 'is dispensed with. The switches, when started automatically operate until the wipers reach the contact corresponding to the position of the sending device.

In the present instance, I have shown my invention as applied to a semi-automatic system, wherein the switches for effecting connections between subscribers are controlled by operators. The controlling device, as shown, consists of several rows of buttons, arranged similar to those of an adding machine. These buttons are arranged so as to connect certain circuit combinations to the-controlling wire or wires which are connected to the automatic switches in a certain order; These control wires are connected in sequence to the wi ers of the various automatic switches. T ese Wipers in turn pass over contacts in banks of the automatic switches. The contacts of these banks are connected in reverse order to those of the buttons of the controllin device. If number 1. button of the contro ling device is set, and the automatic switch is stepping, a circuit will be closed over either one or both of the control wires, when number 1 contact in the banks is reached. If number 10 button is set, :1 ch cuit will not be completed over either of the control wires until the tenth contactin the bank is found. By so arranging the contacts of the controlling device and the contacts of the banks, I am able to pick out any particular contact. Instead of having a sending device for driving the switches, I really have what may be termed a stopping device, for as soon as the wipers of the switches reach the proper contact, a circuit is closed through the control wires and the control device, whereby the switch is automatically brought to rest with its wipers resting on the proper contact.

\Vith the foregoing arrangement, each switch magnet can have its own individual or natural time element, as it simply cbntrols its own circuit and steps the switch until the proper contacts are found.

Another feature of this invention is the extreme rapidity in which connections are efi'ected, as there is no time lost as would be the case were a sending device used. Where sending devices are used, it requires just about as much time to call subscriber 1111 as it would to call a subscriber whose number is 9999. Nithf my invention, it would only require one-ninth of the time to call 1111 as to call 9999, as-there is absolutely no time lost in effecting connections between th various switches.

It will be noted from the foregoing and from the description to follow that the com trol device has no moving parts to work in unison with the switching mechanism. The switching mechanism when active is brought to rest at the proper time by means of certain circuitconibinations set up between the switching mechanism and the control device. This latter device remains passive at all times regardless of the action of the switching mechanism which it controls.

winding of a group relay 3 switch picks out I starts the same hunting 'My invention is illustrated in the accompanying drawings, wherein Figure 1 shows a subscribers line and control circuit. Fig. 2 shows a primary and first selector switch circuit. Fig; 3 shows a second selector switch circuit. Fig. 4 shows a connector circuit. Fig. 5 shows a subscribers line circuit. Fig. 6 shows a key-set control circuit. 'Eig. 7 shows the operators key-set switch circuit. Fig. 8 shows the controlling device. Fig. 9 shows how the combinations between the controlling device and bank contacts are effected.

Referring to Fig.1 the subscriber station is equipped with apparatus usually in common battery systems and the line wires cfi om thisstation terminate at'the central ofiice in a line relay 2. The line relays are divided into groups, there being ten groups to each one hundred lines. The windings of each group of ten relays are common to the so that when any line relay is energized, the group relay associated with it is also energized. The group rela when operated makes the row contact in t e primary switch. busy, while the line relay when test contact in th The switch W is common to a group of one hundred lines and it is made to rotate whenevera call is originated. In rotating this an idle primary switch and for the calling line. Referring now to F ig. 2, the primary switch is shown at C: On the spindle of the switch is mounted a row wiper 63 which passes over the row contacts when the switch rotates.

H pick out the group of calling lines and then steps vertically until the calling line is found. The first selector switchis shown at D and is similar to the primary switch. The spindle'of this switch carries a set of row wipers which engage .row contacts when the switch is rotating and also another set of wipers which engage the vertical rows of contacts after the switch finds the proper row -contact.

All of the primary, first selector, and connector switches are provided with two distinct kinds of wipers, namely,

row wipers to pick out the group while the switch rotates and vertical wipers which pickout contacts primary and key-set switches are only pro kegoard or controlling device.

vided with a single row-wiper while the selector and connector switches are provided with two row wipers The row wipers of combinations in relation to the operators.

ferring again toFig. 2, the wipers 63 of thep'riinary switchC and the wipers 56 oi-the first selector switch 1) are joined 'as indicated. by-the heavy lincs'for conversaoperated makes the individual.

e primary switch busy.-

This switch first rotates to -selector switch in the verti'ciil rows. Thetional purposes. The tip and sleeve (onductors are separated by the condensers 43 and 44. Relay 23 and the retardation coil 26 transmit talking current to the calluig subscriber. Belay 21 is the starting relay of the primary switch and corresponds to the line relay 2, (Fig. l) as it controls the action of the operators key-set switch, Fig. 7. Relay 22 is the row test relay while 2-1 is the individual test relay. Relay 25 is operated when the key-set switch picks out the trunk and remains energized while the of these magnets.

are normally completed through the back contacts of this relay 28,. and so therefore whenever it is actuated the magnet circuits are broken. The action thus set up between the relayand the magnets cause the latter to vibrate and continue to do so until their-energizing circuits are opened. The controlling relays 81 and 82 are connected to the row wipers as shown, and either one of these relays operating when the proper circuit combination is formed between the key board and the contacts which these wipers pass over closes the circuit of the shifting relay 29. The action of this latter relay disconnects the rotary magnet of the first selector switch and in its place connects the vertical magnet. As the first vertical step of the first selector switch the controlling relays '81 and 82 are disconnected from the tip and sleeve conductors of the trunk.

Referring now to Fig.3 the second selector switch at E is similar to that of the first and is controlled in the The two control relays are connected to the row wipers and when either one or both are operated the circuit of the rotary magnet is disconnected and the vertical magnet connected in its place.

Refcrring now to Fig. 4 the connector switch at G isprovided with a set of wipers 355 leading'to. the talking conductors of the same K121111161.

' called line and a test wiper 360 which is also a part of the circuit of the cut off relay. This switch besides having the row wipers 375 and 380 also has a air of wipers 365 and 370. These latter wipers are connected to the row wipers and also to the control relays 305 and'310. In the connector switch' t i necessary to pick out a predetermined individual contact in the vertical row as well as to pick out a predetermined. row contact,

thusnecessitating the. addition l. wiper 35 The Ye ill}; until the wipers 15 or 370 clo; the (in .iit of one or both oi the control reinyn irhen such a Lll'Cllli; 1S closed either one one relays; l v

ring will close the eircnit of ioluy 325, thiireby disconnecting the ELYi magnet anal (to. in the. wipers of the tonne n. switeh to rent. on the vontoets oi the \li lied line. This last notion of either one tho it-mtrol reinys 305 or Kill conneets the test rolny 3-15 to the test wiper 360. It

2n the ca led lino is hr y, the notion at this rol: U. r the rircnit' of the release mag-- net 35!) and rutorc. the so it fh and also place a. suitable bury tourv signal to tho calling sub H the ffflllttii line is n t busy then 25 i O u ill be pliuzod in Series with the eut oti' 1L The net ion of relay 330 dis V, mtrol rel and closes the tip conductors e. the trunk. Relay 4,53%; in die sir reluy and is Operated in- Be trrinittcni L of the commutator 56 0 until the eulletl purtjr' answers. where on ii i iliw nnertetl. llelny 33.;

n20 trmmnit talking fil L tilt:

15 munch. llnj' ock while the (tliing enusixrioer controls the nation 0'? the prinmr UiilSPPH1ECl iteihra g now to .l ig, I.) the suhstribrt b 40 stati n and line co n nent the same as Y Lilli i once being that not shown in do nil. V a". the switch shown timjnnui: to tin Millti'i N, Fig. l

c in idiiswitch.

the heyeet 5 shown. the some The 1- ihe rip and. mlPQYQ side arts! which the wilt: the mliiogj subh tho notion of the. are routxbllo-al. ltlf'l is tho now t at i :l prim out th pnrtioidru" mp 1 uhi h the railing trunk 1:? loifriis the intnviduul toot rewlzen i e trunk in tho group 1W the s gnal relay and no b in crir. with rclu 5.35.. Fig. {o

art-Eng relay and uorresponrls iig. while 133 t e row to 1; Hit. 1 s oporritoil when the mi- 32: iolnplionr for 1-3 sleeve conductors of the trunk. Relay 157 is operated when the starting button 247 is pressed and connects the control relays in scrim with the tip and sleeve. conductors and the wipers of th shifting switch X. \Yhen either one or both of the cmitrol relays are operated the nmgnet f the shifting switch is closed causing the wipern to step on to the. next Contact. The operations l rybo:1rd shown in Fig. consiuts of four rows oi buttons, each row liming ten buttons. The corresponding buttons in ouch ro\ are n1ultipled and lead to buttery, generator. eonrlenser, etc., as shown. The contacts of button number 1 of each row are connected to the generator 230. When number 1 button of any row is pressed, generator current connected directly across tho tip and sleeve control wires. Number 3 button of ouch row is connected to one .side of tin generator 230 and whcn this button of uny row is prt seal the generator is connected to the sleeve control wire. \Vhen number 3 button of any row is presSo g nerator !30 is connected to the. tip control wire. "hen number 4 but ton is pre, ed buttery B 3 is connected directly across the tip and sleeve control wires. \Yhen button 5 pressed the battery is (torn nected to the sleeve control wire and when number 6 button is pressed the. battery is connected to the tip control wire. \Vhcn button uun'iber '7 is pressed tho tip and sleeve control Wires are directly short cireuited. when lnitton number presaed the ground in conmn'jted to the gleam contr l wi e and when number 9 button pressed grouml is; mnnvrtcd to the tip control wire. When number 1 button preused tho condenser 231 is conneeted dircrtly across the tip and sl eve control wires. The control wires trout the various ripg of buttom are connertcd in order to the tip und :Isleerc trunk wires by the nction oi the uhil'ting switch N. At the first step of the switt'h the (imllroi wires of the first row of buttons are. connected t the tip and sleeve eontiuet: n ch in series w'th one of the control rcluvs a: boon. As soon an thew. control role 5 operate. which happens when tho proper circuit combination is be up between the liti board and the wipers (it the s rrtoi' or connector FHVlitllQS; the .Jwitch h takes it J top and di-qeonnecta tho rontrol wirco of the lirnt row of outtanxv and converts the cont-i oi wires of the second set (3i buttons and so on.

The l cy-lmnrd urrnngcinont shown on Fig. 8 will ruin: cure oi un exchange. having ten thousand lines \f-npneity and for larger cxeiuinfics it will only be necessary to arid the net wiry buttons and insert the proper StliClt r switchesv Fig. .l relniww hon the various circuit 0on1- lJlInltlGilS are set up between the key-board or i th? bunk contacts of the. switches. The bit contacts ore sshown at 860 to which but tery, generator and condenser are connected, while a single row of buttons are connected as in Fig. 8. Suppose for instance that number 1 button is pressed and the wipers one terminal of the relay 5 and also closes the circuit of the stepping magnet 7. The stepping magnet operating closes the circuit of relay 6 which in turn opens the circuit 5 850 start to rotate; when the wipers of the of the magnet itself causing it to vibrate and 70 switch reach the first contact to wh h' the step the switch W. This switch will concondenser 831 is connected a circuit wil be tinue to rotate until an idle primary switch closed as follows: ground side of generator such as shown in Fig. 2 is found. As soon 230, relay 840, relay 810, top row wiper of as such a switch is found, the relay 5 is 10 the switch, condenser 831, lower row wiper, placed in series with relay 21, (Fig. 2,) by 75 relay 820, relay 830, contacts of button 1 to the following path: ground, contact of rethe opposite side of generator 230. All of lay 4, 5, 18, W, 14, 21, 70, contact of relay the relays 810,820,830 and 840 are operated. 24 to battery B. The relay 5 operating The action of relays 810 and 820 close the opens the circuit of the magnet 7 bringing shifting or control relay of the switch and the switch W to rest. Relay 21 operating 3 cut oil" the rotary magnet. The action of closes the circuit of the rotary stepping magrelays 830 and 840 close the circuit of the net 31 by the following path: battery shifting switch N, disconnecting the first 80, back contact of relay 24, 71, contact of row of buttons and connecting the next row relay 28, back contact of relay 22, 31 to in order. Suppose number 5 button were ground. The operation of magnet 31 causes 35 pressed then the switch wipers 850 would the switch C to operate until the wiper 64 rotate until the fifth set of contacts are reaches the busy row contact. The wiper reached, whereupon acircuit would be closed 61 is carried on the same spindle with the as follows: negative side of battery B-B, wipers 63 and 65, and while the switch is contacts of button 5, relay 840, relay 810, rotating the wiper 64 passes over contacts 90 top row wiper to ground through the row leading to the group relay 3. As there are contact. The energizing of relays 810 and ten of these group relays to each one hun- 840 shift the control circuits of their redred lines it follows that the wiper 64 in spective switches as before. In case numrotating to its extreme position will pass her 10 button is pressed a circuit will not be over ten contacts. 95 closed until the row wipers of the switch There are ten sets of individual contacts reach the last contact, whereupon the folarranged in vertical rows associated with lowing circuit is closed: ground side of geneach row contact and which the wipers 63 erator 230, row-contact, lower wiper, relay and 65 respectively engage. It follows there- 820, relay 830, contacts of button 10, confore that after the switch picks out the 1 0 denser 231, relay 8 i0, relay 810, upper row group in which a line is calling, it will afterwiper, row contact to the opposite side of ward step vertically until the wipers engenerator 230. The operation of these regage the contacts of the calling line. As lays close their respective control circuits as soon as the row contact is found, the. circuit before. With the arrangement as shown in of relay 22 is closed as follows: battery B, this figure 1 am able to cause the various 80, back contact of relay 24, 71, 22, 64, 13, switches to pick out or come to rest on any contact of relay 3, to ground. The relay '22 desired contact without the use of a sending in operating disconnects the rotary magnet device for driving the switches. It, of 31 and in its place connects the vertical 45 course, follows that various other combinamagnet 30, thereby causing the switch to tions than those actually shown could be step vertically until the bus individual test made and the number of combinations incontact is found. As soon as such a concreased. The switches I have employed tact is found the circuit of relay 24 is closed simply step around ten contacts and then as follows: battery B, -24, 68, contacts of 0 step vertically to the tenth contact to pick relay 22,67,11,contacts-of relay 2 to ground 15 ent the highest number, so therefore it is through the contacts of relay 1. Relay 24 only necessary for me to show circuits for operating opens the wire 71 and disconnects causing ten combinations. In the connector relay 22 which in'falling back disconnects switch individual wipers also pass over rows relay 24 from the wire 67 and connects it 55 of contacts arranged like those shown at instead to wire '66, thereby placing relays 860, Fig. 9. 24 and 1 in series. The operating of relay 1 Other features in connection with the disconnects the line relay2'and the group various figures will be brought out in the relay 3. Relay 24 connects battery to the detailed description of operation. windings of relays 23 and 25 and the falling 50 The operation of my system is asfolback ofrrela 22 connects ground t0"the 126 lows: The subscriber at A upon removing coil 26, there v supplying the calling subhis receiver closes the circuit of the line relay 2 in series with the group relay 3. This latter relay operating closes the circuit 65 of relay 4 which in turn conne ts ground to scriber with ta king current.

Relay 21 remains energized until an primary switch finds the calling line and until the key-set switch finds the trunk. 130

. with relay 152 by the Relay 21,. when first actuated, places battery on the wire 79 to relay 130 and also places battery to wire 62 which is connected to the individual test contact of the key-set switch, (Fig. 7.)

Relay 130 closes the circuit of the stepping magnet 133 of the switch Y through the normally closed contacts of relays 131, 132. The magnet in operating closes the circuit of the interrupter relay 134, thereby causing the magnet to vibrate and the switch to rotate until an idle key'set switch is found. WVhen such a switch is found as shown in Fig. 7, relay 131 is placed in series following path:

round, contacts of relay 130, 131, 138, Y, 140, 152, 195, 196, 197 to battery B through the opcratofls jack 400. Relay 131 operating places battery on wire 136 to relay 132. As soon as this latter relay operates, ground is placed on the wire 138, thereby shunting relay 131. This direct ground placed on wire 138 makes the wire 140 which is multipled to other Y switches busy, The operating of relay 132 also places ground on the row wiper of the key-set switch by the following path: ground 139, Y, 1-11, to the row contact.

he operation of relay 152 connects ground to the rotary magnet 165 through the back contact of relay 153 causing the switch M to rotate. This switch will rotate until the busy row contact is found, whereupon the circuit of relay 153 will be closed as follows: battery B, contacts of relay 152, 176, 153, 171, 168, 141, 139, contacts of relay 132 to ground. The key-set switch M operates in the same manner as the primary switch.C, (Fig. 2.) Relay 153 disconnects the rotary magnet 165 and connects in its place the vertical magnet 164, thereby causing the switch to step vertically until the busy individual test contact is found. The finding of this contact closes the circuit of relay 154 515 follows: ground, 154, 172, 62, 80, contacts of relay 21 to battery B. Relay 151 disconnects relay 152, thereby cutting off the vertical magnet and causing the keysct swit h to rest on contacts leading to the calling primary trunk. Relay 152 becoming disengaged opens the circuit of relay 153 and this latter relay in falling back places relays 156 and 25 in series by the following path: ground, back, contact of relay, 153, 175, back contact of relay 157, 202, contact f relay 155, 156, 193, contacts of relay 158, 170, 59, 25 to battery ll through the contacts of role. 24. The operating of relay 25 (Fig. disconnects relay 21 and also relay 5, (Fig. 1). The releasing of relay 5 trees the switch 7 allowing it to pick out other primary switches. Relay 156 operating places loattcry on wires 181 and 183 causing the lamps 24 5 and 244, (Fig. 8,) to light. As soon as relay 21 in F ig. 2 became disconnected batcontacts of 158, 170, wiper tery was removed from the individual test contact of the key-set switch, thereby allowing relay 154 to fall back. Relay 21 also releases relay 130, thereby restoring relay 132 so as to allow the switch Y to be used by other trunks in picking out key-set switches.

In the present system I have provided ten primary switches such as shown in Fig. 2 for each one hundred lines. Each group of ten primary switches is in turn provided with one switch for picking out idle key-set switches. The percentage and grouping of the trunks and lines can be varied to suit traliic conditions.

The wire 141 leading from the Y switch to the row contacts of the key-set switch is not multipled. The Y switch picks out an idle key-set switch and then places ground on the row contact of the selected switch and these row contacts are not multipled. This arrangement prevents interference between other Y switches and also between the keyset switches. In no case is ground placed on more than one row contact of any key-set switch at the same time.

In Fig. 1 the switch W is individual to one hundred lines and picks out a group of primary switches, and in this case the row contacts of a group of primary switches are multipled.

The li hting of the two lamps 243 and 244 noti es the'operator of a call, and she then presses button 248 closing relay 155. The operation of this relay connects her telephone set across the trunk wires, disconnects relay 156, thereby extinguishing lamps 243 and 244. The lamp 245 is lighted when the relay 155 is operated. The disconnecting of relay 156 also opens the circuit of relay 25,

(Fig. 2, whichin falling back closes the tip and sleeve conductors of the trunk, allowing the operator to converse with the calling subscriber.

The operator upon receiving the number desired, which we will assume is 1470, sets up this number on her key-board (Fig. 8) in the following manner. She presses number 1 button in the row B, number 4, in the row S, number 7, in the row T, and number 0 in the row U. The row R represents the thousands, the row S the hundreds, the row T the tons and the row U the units numerals of the desired line. After setting up these buttons she presses the starting button 247 closing the circuit of relay 157 as follows: ground, contacts of button 247, 186, 157, 193, 169, 59, relay 25 (Fig. 2), contacts of relay 24 to battery B.

The operating of relay 157 disconnects rela 155 and at the same time extinguishes the lamp 245. The energizing of relay 157 places the relay 840 (Fig. 7) and relay 81 (Fig. 2) in series as foiiowsz ground, contacts of 0, contacts of relay 157, 840, 151,

167, 61, 53, 81, 46, Wiper 48 to battery B B through the contact upon which it normally rests. The energizing of relay 81 closes the circuit of relay 29 as follows: ground, contacts of 81, 42, cam springs 41, 36, 29, 45, contacts of relay 25 to battery B. The energizing of relay 29 closes the circuit of the rotary magnet 34 as follows: battery B, contacts of relay 28, 71, contacts of relay 29, contacts of relay 27, cam springs -10, 31 to ground. The operation of magnet 31 causes the switch D to rotate. The operation of lay 810 (Fig. 7) closes the circuit of the magnet 161 of the distributing switch causing the wipers to take one step. These wip ers in stepping, disconnect ground from the relay but connect this relay to wire 22] which is common to certain of the buttons in the first strip. The relay 830 is also connected to the wire 220 which is also common to certain buttons in the first strip.

When the wipers 48 and 49 of the switch D reach the first contacts, a circuit is closed as follows: generator 230, (Fig. 8), contacts of button number 1, 220, N, 830, 150, 60, 82.

47', 49, condenser 831 as shown in (Fig. 9), wiper -18, 46, 81, 53, 61, 167, 151, 810, contacts of relay 157, 0, 221, contacts of buttoni 1 to ground. It will be noted that as soon as the wipers 48 and 49 leave the contacts upon which they normally rest, the relays 81 and 82 and also relays 830 and 810 are deenergized, as the contacts are spaced so that the wipers 18 and 49 always leave one set of contacts before they engage another set. When the relays 81 and 82 are closed the second time by the circuit just tra ed through the key-board, they close the circuit of relay 27 as follows: ground, through contacts of relays 81 and 82, 42, cam springs 41. 27, 45 to battery B through the contacts of relay 25. The operation of relay 2'7 disconnects the rotary magnet 3-1 and in its place connects the vertical magnet 33, and the switch D starts to step vertically to pick out an idle trunk leading to a second selector switch.

The operation of relays 830 and 8 10 (j'lfltst, the circuit of the stepping magnet 161. thereby disconnecting the relays 830 and 840 from the first strip of buttons and c nnect them instead to the second strip of buttons.

The relay 27 will remain energized until the test wiper 57 finds a contact free from ground, which is the indication of an idle trunk. The relay 27 also has its circuit maintained through the normally closed contacts of relay 28, and to ground through the release magnet 32, as this magnet has groundccmnected to its winding by the action of the cam springs -11. When the wiper 57 is in the center of a test contact, free from ground, and the relay 28 is energized by the action of the magnet 38, then the test relay 27 will become denergized and close the tip and sleeve trunk conductors. While this rela is energized in picking out the idle trunk, t e trunk conductors are separated preventing any interference, While passing over busy trunks. At the first vertical step of the switch D, the wipers 48 and 49 are disconnected from the row contacts, thereby preventing any further action of relays 81 and 82.

As soon as an idle second selector is picked out, such as shown in Fig. 3, the circuit of relay 811 is closed as follows: ground, cam springs 41, 75, 32, 72, contacts of relay 28, 58, test wiper 5'7, 96, 811 to battery B. The energizing of relay 811 closes the circuit of the rotary magnet 87 follows: battery B, contacts of relay 811, contacts of relay 83, 91, cam springs 106, 99, 87, 100 to ground through the contacts of relay 822. As soon as the row wipers 103 and 104 reach the fourth set of contacts such as shown in Fig. 9, a control circuit is completed as follows: battery B B, contacts of number 4 button in the row S, 222, N, 830, 160, 60, contacts of relay 27, 51, wiper 56, 90, 84, 97, Wiper 103, fourth set of contacts, such as shown in l ig. 9, wiper 104, 98, 85, 91, 56, contacts of relay 27. 53, 61, 167, 151, 810, contacts of relay 157. 0, 223, number 4 button to ground. The operation of relays 84 and 85 close the circuit of the relay v83 by placing grmind on the wire 96. The operation of this relay 83 disconnects the rotary magnet 7 and in its place connects the vertical magnet 88 causing the second selector switch I) to step vertically and pick out'the idle connector switch. At the first step of the switch E, the wipers 103 and 101 leave the row 4 NltflOtS and the relays 84 and 85 are disconnected.

The operation of relays S30 and 840 cause the distributing switch to take another step and disconnect these two relays from the second strip of buttons and connect relay M0 to ground as in the first instance. The tcst relay 83 will remain energized until an idle connector found, such as shown in Fig. 4. The action of this relay 83 is controlled in the same manner as relay 27 (Fig. 2), and while it is energized it sever-s the tip and sleeve conductors preventing interference while the switch wipers are passing over busy trunks. As soon as this relay 83 becomes dei nergizcd, the following circuit is established: ground, 0. contacts of relay 157, 840, 151, 167, 61, 53, contacts of relay 27, 56, 91, contacts of relay 83, 101, 302, contacts of relay 330, 324, relay 310, 322, wiper 380 to battery 11-11 through the contact upon which it normaltr rests. The operation of relay 310 over this control circuit closes the circuit of the relay 315 as follows: battery l5, contacts of relay 310, 2309, cam springs 397, 311, 315, 308, 102,

' terrupter relay "v85.

93 to ground through contacts of relay 822 (Fig. 3). The operation of relay 315 closes the circuit of rotary magnet 390 as follows: battery B, contacts of relay 325, 333, contacts of relay 315. contacts of relay 320, 318, 390 to ground through contacts of the in- The action of this magnet causes the switch G to rotate.

The operation of 840 causes the shifting switch (Fig. 7) to take another step, disconnecting ground from the relay 840, and con nccting this relay and the relay 830 to the third strip of buttons. When the wipers 375 and 380 of the switch (1 reach the seventh set of contacts as shown in Fig. 0, a control circuit is established as follows: battery B-B, number 7 contact, wiper 375, 321, 305, contacts of relay 330, 301, 101, contacts of relay 83, 00, 50, 54, contacts of relay 27, 60, 107, 150. S30, N, 221, contacts of button 7 (Fig. 8) 0, contacts of relay 157, 840, 151, 167, (51., 53, contacts of relay 27, 5(3, 01, contacts of relay 83, 101. 302, contacts of relay 330. 324, 310. 322, wiper 380, number 7 contact upon which it rests to ground. The operation of relays 305 and 310 connect battery to the wire 300 and close the circuit of relay 320 through the cam springs 307 and 303. The operation of relay 320 disconnects the rotary magnet 390 and in its place connects the vertical magnet 395. The operation of this magnet causes the switch G to step vertically.

The operation of relays 830 and 810 (Fig. 7) cause the shifting switch to take another step, disconnecting these relays from the third strip of buttons and connecting them to the fourth strip of buttons. The switch G (Fig. 4) will continue to step vertically until the wipers 305 and 370 engage the tenth set of contacts, whereupon a control circuit is again established as follows: generator 230, number 10 contact, wiper 365, 321, 305, 323, contacts of relay 330, 301, 101, contacts of relay 83, 90, 5G, 54, contacts of relay 27, 60, 167, 150, 830, N, 226, number 10 button, condenser 231, number 10 button, 227 0, contacts of relay 157, 840, 151, 167, (31. '3, contacts of relay 27, 50, 91, contacts lay 8. 101, 302, contacts of relay 330, 324, 310, 322, wiper 370, number 10 contact to ground.

The operation of relays 305 and 310 again place battery on the wire 300 and close the circuit of the relay 325 through the cam springs 397 and 398. hen the switch (I was first rotated, it disconnected the relay 315 from the control wire 300, and in its place connected the relay 320 so that it would be operated at the proper time. When the switch G steps vertically, the relay 320 is disconnected and the relay 325 placed in position to be operated by battery laced on the wire 309. The operation of 325 disconnects battery from wire 333 and prevents any further action of either the vertical or rotary magnets.

The operation of relays 830 and 840, when this last contact is found, causes the shifting switch to disconnect them from the fourth strip of buttons and the step which accomplishes this also closes the circuit of the relay .158 as follows: battery ll, 1, 1.87, 158 to ground. The operation of this relay closes the circuit of the stepping magnet- 161 and also places ground on the control spring 231 so that it can operate the relay 163 and interrupt its own circuit. The interrupting circuit thus established causes the shifting switch to rotate until it reaches its normal position. Just before reaching this position, the wiper of P closes the circuit of the re' lease magnet 166 of the key-set switch M causing it to restore to its normal position thereby disconnecting the operator and the controlling device from the main trunk.

Referring now to Fig. l, as soon as the relays 305 and 310 become deenergized after their last action, the wipers of the switch G are in engagement with the contacts or the wanted line and the relay 330 is connected in series with the cut-oil relay of the called line as follows: battery B, contacts of relay 305, 336, contacts of relay 325, 326, 330, contacts of relay 310, wiper 360 to ground through the cut-off relay of the called line. The relay 330 now becoming energized places battery to the tip relay 33-5 and ground to the retardation coil 340, thus supplying talr'ng current to the called line. The action of this relay also closes the circuit of the ringing relay 350 as follows: battery B, 329, contacts of relay 325, 331, 350, commutator 500 to ground. The test relay 315 was connected to the wiper 360 when the relays 305 and 310 were energized the last time and it the line had been busy, the relay 345 would have become energized and closed the circuit of the release magnet 335, restoring the switch G to its normal position. This relay 345 will remain energized by ground over the test wire 308 and connect a suitable busy tone to the calling subscriber notifying him that the line was bus T he ringing relay 350 will act at intervals and place generator to the called line, and when the called subscriber removes his receiver during a silent interval, the tip relay 335 will become energized. The energizing of this relay disconnects the two relays 320 and 315 by disconnecting battery from their locking contacts and also places ground on the test wire 308 rendering the connector switch busy so long as he has control of it. When the relay 320 falls back it removes battery from the locking contact of relay When relay 325 falls back it disconnects battery formerly supplied to relay 330, through the contacts of relay 305. The eircuit of relay 330, however, 18 maintained by the action of relay 335 which places battery to the winding of relay 330 before the relay 325 falls back. After the parties are through talking, the called subscriber, upon hanging up his receiver, causes the relay 335 to fall back and close the'circuit of the release magnet 385 as follows: battery B, contacts of relay 335, 314, contacts of relay 315, 385, 322, cam springs 397 to ground. The ac; tion of this release magnet restores the switch G to its normal position. The calling subscriber upon hanging up his receiver causes the tip relay 23 (Fig. 2) to fall back, thereby closing the circuit of the release magnet 32 as follows: battery B, cam springs 38, 73, contacts of relay 23, 58, contacts of relay 28, 72, 32, 75, cam springs 41 to ground. The operation of this magnet causes the switch C to return to its normal position opening the cam springs 38, thereby removing battery B from the wire 73 allowing the circuit of the release magnet 35 of the switch D to become energized over the following path: battery B, 35, 73, contacts of relay 23, 58, contacts of relay 28, 72, 32, to ground through the cam springs 41. The operation of relay 35 restores the switch D, thereby opening the cam springs 41 and disconnecting the energizing circuit for the release magn ts. As soon as the test wiper 57 (1f the first selector switch leaves the test contact, then the relay 811 (Fig. 3) falls back and closes the circuit of the release magnet 86 as follows: battery B, contacts of relay 811,

86, 89, cam springs 95 to ground. The operation of this magnet causes the switch E to restore and open the release circuit.

In case the called party does not answer, then the calling party has complete control of all the switches and releases the primary, first and second selectoiis in the manner Just described. The releasing of the second selector switch (Fig. 3) removes ground from the test wire 308, disconnects all three relays 315, 320 and 325, thereby closing the circuit of the release magnet 385 ust as though the called subscriber had answered and then hung up his receiver.

It will be noted that two separate control relays 8]. and 82 are shown in Fig. 2, but in practice it would be advisable to combine these two relays in one, having two separate windings. This would also be true in connection with the control relays 84, and 305, 31.0 and 830, 840.

In Figs. 2, 3 and 4 I have ShOWII VHI'IOUS circuits shifted by means of cam springs operated by the switches D, E and G. flhese cam springs of course are to be ad uSted so that only one circuit will be established during any one action of the control relays 81, 82 and 84, 85 and 305, 310. For instance in Fig. 2 relay 29 is operated through the normally closed rotary cam springs 41 by the action of either or both control relays 81 or 82. These relays are deenergized bythe wipers 48 and 49 leaving the contacts or by the action of the shifting switch (Fig. 7) before the cam springs can conmeet the relay 27.

Having thus described my invention, what I desire to secure by Letters Patent is:

1. In a telephone exchange system, a plurality of lines, automatic switches for interconnecting the same and a control device therefor comprising means to selectively associate with said switch, circuits of different electrical dimensions irrespective of the state of activity of the switch, and control magnets for each switch responsive to control from a circuit of an electrical dimension dependent upon the position of the switch.

2. In a telephone exchange system, a plurality of lines to be interconnected, automatic switches for interconnecting them, and control means for said switches comprisin a digital set of control circuits at a contro station having individually permanently established electrical dimensions, a coacting set of circuits associated with each switch, and switch control magnets arranged to be connected with said circuits for control thereby.

3. In a telephone exchange system, a plurality of lines to'be interconnected, automatic switches for interconnecting them, and control means for said switches com prising a digital set of control circuits having different but immobile electrical characteristics, a switch control magnet for each switch responding to control over one or another of said control circuits depending upon the position of the switch, and meansto associate any desired one of said control circuits with said switch control magnet.

4. In a telephone exchange system, in combination switching mechanism and contact arms therefor, contacts associated with said switching mechanism engageable b said contact arms; an operators key-boar actuating means apart from said key-board for the switching mechanism, a control circuit extending between the switching mechanism and key-board; means rendered operable over said control circuit when the contact arms engage contacts corresponding to the indication on the keyboard, to disable said actuating means and disconnect said key-board.

5. In a telephone exchange system, in combination a link circuit comprising a series of automatic switches and contact arms therefor, contacts for the automatic switches engageable by the contact arms, an operators key-board consisting of a series of rows of keys apportioned to the automatic switches, actuating means apart from said key-board for said automatic switches. a control circuit extending between the automatic switches and key-board; means rendered operable ever said control circuit to disable the actuating means of an automatic switch of the series when its contact arms engage contacts indicated by its apportitmed row of keys, together with means in said control w'circuit for connecting the next row of keys in the series.

6. In a telephone system. the combination with an automatic switch having a bank of contacts and contactors associated therewith, of means for designating the contact to be connected to a cont-actor, means intiependent of the designating means for actuating the switch Kind means 'l'or disabling the actuating means when the contactor engages the contact designated.

7. In a telephone exchange sytein, the combination of a switching: mechanism having a bank of contacts and a contactor as sociated therewith. a plurality of ccanbina tions of circuits ass'r'ariatcd with certain of the contacts. another plurality of combinati ns of circuits adapted to be connected one at a time with the cont actor, means for actuating the switching mechanism to move said contactor into successive engagement .with the contacts, and means for disabling the actuating means when the contactor engages a contact, the circuit of which is: energized by the engagement ot said contact. by the contactor.

8. In a telepl'ione exchange system, the combination with switching me hanism lltl-'-- ing contacts and contactors s.) -'atied therewith. of a plurality of comhii'iations of circuits connected with certain of the conta ts, another plurality of combinations of ci1= cuits including a circuit passive tor connecting the other circuits with the contactors, means for actuating the switching; mechanism to move said contactors successively into cngagcn'ient, with the contacts, and means associated with the passive circuit for disabling the actuating means when the contactors engage mntacts, the circuit in which said COlittiCtn are included being energized by the engagement of said contacts by the contact'irs.

9. In a telephone exchange system, the combination with witching mcchanisi'n hav ing contacts rnd contactors as-rsociatcd there with, a plura' ty of combinations of circuits connected with ertain of the contacts, an operators keyae t. another plurality of corn binations of circuits ciate-L'l w ith the lacy set, it ans including a key and a circuit for connecting;' said other combin ttions of cir cuits with the contactors on the switching mechanism, means for actuating the switch ing niecl'iani m to move the contactors into successive engagement with the contacts, and means for disabling the actuating means when the contactors engage certain contacts, the circuit in which said contacts are included thereby forming a part of and completing the connecting tll'tlllt.

it). ln a telephone exchange system, the combinati n with automatic switching mechanism having contacts and wipers associated therewith, lines terminating in certain oi" the contacts. one oi the w pers adapted to engage s'aitl contacts coin ttetl to said lines. a plurality of combinations ol circuits connected with certain other contacts. an operators hey set. another plurality of combinations of circuits associated with the key t't. means. including keys t'or designating the line and contact wanted, and a circuit for connecting said other combinations of circuits to certain of the wipers. means for actuating: the switching: mechanism to more the wipers into successive engag ment; with the contacts. means includin a relay in said connecting circuit for disahlii'ig the act'uating means. the connecting circuit being completed and becoming active when wipers engage a contact or contacts of said other contacts designated hy the hey. thereby ere'izing the relay and bringing the wiper adapted to engage contacts connected to said lines to rest on the contact aszwiated with the line wanted.

11. In a telephone exchange system, the combination with ant anatic switching mechanism having cmitacts ar ata-iatc l therewith, of actuating: means tor the switching inc-ch anism, a, wiper adapted to engage certain of the contacts, other wipers adapted to cooperate with certain othrr contacts and at times to establish circuit comhinations to disa le the actuating; mean and hring the first-mentioned wiper to rest in engagement with a l)I'Qtltt'*ltl'litlttl t 'l llttt 't.

l). 111 a telephone exchange systcm. the combination with automatic switching mechani m including selector and connector switches having hanks of contacts and corn ta -tors associated therewith. ot linlt circuits intcrconuc tinit the switches, suhscrihti's lines terminating in the connector switches, actuating means for the switches. a plurality of combinations of circuits connected with certain of the contacts, an opera or's key set conprising a plurality f rowsot lUfV another plurality of combinations of ciicmts a.-'. oci.=itetl with the operators key set and controlltal by said keys, means for connecting the circuit combinations designated'ty a key or larva depressed in sncces aion to the selector and connector switch contactors. and means for ili-:.l ltl2ff he actu ating meant ot each swit h when the confactors thereof engage contacts in the .switch designated by a licy or lieys d pressed.

l3. Controlling syst m tor automatic switches comprising testing means it .-.oci1ttl with each switch and adapted to connect i it) ill) sumessiveiy with dif'mrentiy test (circuits and mums for mmezsin testing means mspmisive to a 1 i one of said tust vii-wits :0 d1. ating mans o'l' Lhi; usxm'iniwi 14'. ihltonmtiv .wiitchi i 1 phonv uxchnngw cumgnmmg zmtuinmic win-hing mevhrmixm Maptmi t-u mum-- mucwsiwly 'WiKii :iii'i'mont cmmwiiw: ('uits, differently :11unwlm'izmi inst cirwaizs :wmciatod \s M1 mid cumwcin; uii his (215E i di'cntiy uhzu'm*icrimd zrontr-w QiILUi-qa each corresponding in :x. \iiihn'ent i, itin'uiig 1111?; testing means asocmu-d \Hii: amid Q 1mg" circuits operatim only when m.) 'mzsapmiding churacterlzed ciruuihs are connected. in series.

15, The method m" mleciix 01y curmm'ting a givvn connveting iii jli lfille "it with any desired one of 1, im vircuits to extend, 2: m .411 imihwi consists in maintaining unnw'zinn each of said group of circuits u diii'ai' characterized testing amidibion, at Wili mblishing u t Sting couditimin said giwn circuit adapted is) cum/6 wzah ha hating: condition appertaining 0 the particular vircuit with which cuzmectiun of the group desired, and determining the desired con nection through the coaction of said Q0mlitions.

16. The method of selectively nnimrt n g a giirill connecting; telephone cinzuii. with any esired one of a group 01" i 7-;t n:-iun Q1!- cuits to ext-end u culincwtiun W1 11 method vonsists in maintaining in 001". with eavh (if Said groups of vii'mi" 7 wnfly 'il1H'iiPfQl'i. .(:d testing (walbiiiiau, at ianiiahin" :1 tusting mditis'ci 0;: mid iiiiCllii, adapted to mnci; Yi'i; w imt condition appertaining tn ln ar-iriicuinr z: cuit with \YhiiTii mminn in the group i: (iLSiiCd, sliccvss vqy bringing" the lillhillt, 1 of said giwn sircuit inn; jlLx qmsitiun with th ham; ads of hp 9i Hits of said group imiil countimi of said comiitiul'ir; lizr-ditfvg 1m dPiurmining {he desired cmmcutinn tiiruugh the couvtiun of said mmiitiw In ti ninmny \YiiOlfG-f 1 m my a gnaiuw in 1n." ncu of two \liirlcmeri. 

